Allen W. Duck

Allen W. Duck has submitted responses to the following questions.

Problems With Skewed D-Pak Components
This is likely the transition of solid to liquid not occurring across the parts at the exact same time. You ...

Is Rework Unacceptable?
This is a little unrealistic given the nature of the processes involved and the variables that we work with every ...

Lead Free Reflow Oven Zone Count
A small EMS with the potential for multiple changeovers a day, high mass and low mass PCBs would be as ...

Puzzling PCB Reflow Delamination Problem
I would suggest you look at the interval between each step and the storage conditions the PCBs were subject to ...

Lead-Free Profile Using Leaded Paste
The increase in the needed energy for good lead free solder joints to be formed is significant. If the target ...

SMT Components Popping Off During Reflow
This is more likely a consequence of out gassing. The components, the PCB, or the paste may be moisture heavy ...

Lifted Leads on QFP
Are the leads lifted or has the solder wicked up the lead leaving the pad/lead interface dry? If this is ...

Soldering lead-free component, with tin-lead solder
With a device of this size and complexity, the issue will be thermal consistency across all the I/O positions. In ...

Reflow oven testing and calibrating concern
There are various industry accepted test panels and measurement systems that provide a "baseline" for comparative analysis purposes. As an ...

Solder Components to Thin Flexible Circuits
Using a Vapor Phase will provide an Oxygen free solder environment for best solder joint results. It will also guarantee ...

Solder Deposits on Components During Wave Soldering
Typically component bodies are made from Non Wetting materials. Solder bridges between leads of a device or across devices can ...

BGA Voids
My understanding is the additional 2% Ag adds tensile strength to the joint as its primary benefit. I do not ...

Concerns with HDI
High Density typically infers higher mass, higher complexity and higher cost. Higher Mass and Higher complexity in a standard convection ...

Optimize Temperature Profile for High Mix Board
High mix circuits have always been a challenge and as the alloy temperatures increase the challenges increase. Trying to manage ...

Flux Deposition
It is highly unlikely that a dipping process is NOT providing adequate Flux. Depending on the nature of the joint ...

Rework Metal BGA's
The issue with any BGA is mass related, and profile to the circuit. Getting enough energy into the device is ...

Component Shift During Reflow
Component shift back onto its pads is a result of surface tension in the molten joint. Shift OFF the pads ...

Ultrasonic cleaning PCB's after wave solder
The issue of the PCB temperature will have more to do with the cleaning chemistry you are using and what ...

Wire stripping insulation prior to tinning
If the wire being stripped is multi strand - Yes. It will keep the wire structured prior to tinning and ...

SMT adhesive problems after wave solder process
The adhesive is either not cured completely or is not wetting to the surface of the PCB. The cure process ...

Tombstone problems
A Tombstone is created as a result of imbalance in the wetting forces across the part. This can be a ...

PCB Singulation
PCB singulation is the process of removing multiple pieces [PCBs] from the matrix they are carried in through the assembly ...

Depaneling equipment
For V score panels the number of suppliers is considerable and each will offer a system based on two opposed ...

Proper handling for raw boards
I dont believe there is an industry standard but "Tacky" cleaners can be purchased that ensure the bare PCBs are ...

Solder cracking specs
We have studied the effect of bending loads on components and joint integrity with particular focus on the effects of ...

Should we buy new low cost assembly equipment
It would be safer to break In-line Printers out for the reason of Vision Patents and the potential for infringement ...